Gear tooth lead testing device



IN V EN TOR. 624,3 6 C? 742 Y G. c. RAZOR 2,612,701

GEAR TOOTH LEAD TESTING DEVICE 2 SHEETS-SHEET 1 B E 5 I ,s'rnvwvfys,

Oct. 7, 1952 Filed Oct. 29, 1945 G. C. RAZOR GEAR TOOTH LEAD TESTING DEVICE Oct. 7, 1952 2 SHEETS-SHEET 2 Filed Oct. 29, 1945 INVEN TOR.

FTTIFNEYS.

Patented Oct. 7, 1952 umrrn STATES PATENT OFFICE GEAR Too'rrr LEAD TESTING DEVICE George C' Ra zor 'Detroit, .Miclr}, assignor to Michigan Tool Company, Detroit; Michu', acorporation of Delaware Application October 29, 194 5, Serial No. 625,139

2 Claims. (o1.2s+ 1'7915) are; also corn plicated an require considerable v Therefore,- a low costLtestifig device, sufficiently siiiipleii'n assimilate. be-us'ed by. relatively un skilledor.seiniskilleddaloor toquickly and accurately chlt..the lead. on gear teeth, will have great 1 ap l eal tof. g"ar, manufacturers. I I

rush-maria sheet. or. this ih'vention .is. to provide I a. gear teeth. l'a'd. testing. device which. req-hreslittle setup. sncrwmeh permits mount-.- ondisfii'ouiitihgof the. g'e'arvto be checked withoutldistui -hin'g' diamante of the. apparatus. To 'ae'sumpusfitmature gear to he checkedis su pbrteaztnataperea, overhanging en'dIof a nia'ndifel thereohj Aiiothfi ohjeit off. this. invention is to provide a cohstri'ictioi'i with which the leadlon gear teeth s checked by comparison. with a. master. gear or a master element having a helical groove.

' 5-5 or Figure 4 tomore'. clearly show the tapered ends providedfor the teethusedin the modified construction asdepicted in ,Figu're 4.

With this gear tooth lead testing device; a, master gear or master elementand a gear to lie..- checked are rotatably mounted on a reciprocable mandrel. A follower contacts .theinaster gear or master elernentwhich'ever is used. An. indicator with a feelerelement.similarly contacts. thegear. Thus, as the mandrel reciprocates, the', ,iriaster gear or master eremem. and gear. to be, checked.

move relative toztheifollower and indicator. -.The follower, following..the.le'ad of the. master. gear or element effectsthe rotationof the mandrel in accordance with. said lead, and with-it the; gear to be checked, permitting the indicator to check.

the lead thereon.

To accomplish this the master gear orthe master elenient' and; r to be checljze'd are mounted upon matu e rotation of which is 'the'gear might be checked as it w h.

A further o'b'ject of this invention is to provide a low-cost gear teeth, lead testing device which may be operated byrelatively'unskilled or semi- Figure Z'is aironteleva-tio'n of the device shown Figure 1'.

Figure 3 is a right'side' elevation'o'f the device shown in Figure lgwit-h the indicator support broken away, showi'i'ig clearly one of the V -shaped a ertures piovidedi'to support the mandrel.

a "gur'' 4' is" a front'elevation of a. modification or. invention.

sigma 5 is an. elevational View. taken on line a.

master gearo'r master element,

'For a detailed description of. the app aratuslthe figures show. abase generally indicated at l; This base may be. an integral casting suitableior mounting the V apparatus. on a table or other standard and providesa substantially flatplatefr] like surface to which are anchored in spacedand parallel relation twoupwardly. directed supports 2 and 3. their upper edges, with V-s'ha'pedjapertures 4 and 5 one of which is c1eai1yindicated in Figure, 3. v These apertures havev edges. 6 and? which serve.

to support a mandrel s ror, reciprocation and.

rotation therein. Bars 4 9.. and I0. overlying .,t hev ul pr edges of these supports are guided for.-

moveinent onstuds II- and are constantly and yieldingly urged toward the mandrel by means of coilsprings [2 held. under compression between the bars and. nuts I3. which threadably engage said. studs and thus. yieldingly maintai said 3 mandrel within said V-apertures It also that the mandrel overhangs such pointed out supports.

'At the left end of the, base,.,asf viewed i nIFf-i'g ures '1 and 2,19; a post Hi anchored tothebfalsie. At the upper end of. the. post, an operatingllevei" I5 is pivotally mounted, asby means of. fulcrum screw 15. The lever hasat itsinner end a m 16. which engages in an annular, groove, i-II on. the periphery of. the mandrel atone of its overhang-- ing ends. Itwillbe cruiteobvious that upon osciliarmgi theilever', the mandrel 8 will be. re'qiprm Gated without restricting its. rotation.

A aster gear [8 master gear is shown and de erted, itis obviousthe side-walls of which have. a helix angle corre- Such supports are each. provided; at

is secured perms; malar a lie.- tween the spaced supports' 2. and 3; While a sponding to the helix angle of the gear to be.

checked. Thus mounted on the mandrel, the master gear or element is laterally positioned with respect to another support [9 anchored by means of bolts 29 to the base l., This support carries a follower consisting of a plunger 2| arranged in radial relation with respect to the axis of the mandrel and master gear, its end adapted to engage the flanks of the teeth of the'master gear or the side walls of the helical groove on a master element, depending, of course, upon which is used. This support further provides two upwardly directed arms 22 and 23, with openings 24 and 25 respectively. A screw 26 projects through opening 25 in arm 23 and a coil spring 27,- surrounding said screw, is held under compression between the inner face of arm 23 and the adjacent face of plunger 2! to constantly and yieldingly urge the follower in contact with the master gear. ably engages a tapped opening in plunger 2!, it

I will be observed that the follower may be removed from the master gear by pullin the plunger outwardly away from said master gear by mean of knob 28 on said screw when desired.

With the master gear thus mounted and provided for, a gear to be checked, indicated at 29,

may be Secured to the mandrel. -In order to mount this gear in such manner that the balance of the apparatus will not be disturbed, the same is mounted upon the other overhanging end of the mandrel. Said mandrel is provided thereat with avery slightly tapered outer end 30 upon which to dispose the gear so as to be rotated and reciprocated therewith. It i to be understood, of course, that this gear is supposed to be of the same size and character as that of the master gear to which itis to be compared.

This checking of said gear is accomplished by means of an indicator 3! mounted upon a'fourth support 32. Such support is mounted upon the base perpendicular to the mandrel and opposite tapered portion 39. Said support is provided with a slot 33 through which bolt 34 extends to permit adjustment toward and away from the mandrel and carries a post 35 upon which .the indicator 3! is adapted to be placed. Such indicator is the conventional type provided with a feeler element 36 which has an end of the same shape as that on the follower plunger. A dial 3'! and pointer 38 on the face thereof indicate the movement, if any, of the feeler. This feeler on the indicator is disposed to contact the gear to be checked in a manner similar to that in which the follower contacts the master gear.

The indicator 3! is then set preferably to zero and the lever l5 oscillated. This effects reciprocation of the mandrel and the master gear and gear to be checked relative to the follower and indicator. Simultaneously, the follower serves to cause the mandrel to rotate in accordance with Inasmuch as this screw 26 thread- 4 I of the bell crank engages mandrel 8 in substantially the same manner as lever l5 engages it. That is to say, an annular groove 42 is provided in the periphery of mandrel 8 adapted to receive pin $3 in the end of the arm of the bell crank. The other end of the bell crank engage a cam- 44 mounted for rotation upon shaft 45 in support 2. A coil spring 46 may be provided for constantly maintainin this end of the bell crank in' engagement with the cam. Thus, when the cam is rotated, by any suitable means such as a crank at the end of shaft 45, the oscillating movebeveledor pointed as indicated in Figure 5. On

the support 2, a ball d'l-or rounded member is secured in a plane parallel to the longitudinal axis of the mandrel in position to engage one of the pointed ends of theteeth on the master gear I each time the mandrel is moved to its leftward limit of movement. This ball is positioned oif center of such teeth, as indicated in Figure 5, so that as the gear engages the same, it will rotate the master gear through a part of a tooth angle. At the opposite end of said master gear, a tapered collar .48 is fixed to the mandrel so that when the master gear moves to the left, the follower will pass out beyond the right end of said gear onto collar 48 just before the tapered teeth on the left end engage the ball 41. This frees the master gear, permitting it to rotate a partial turn due to engagement with the ball 61. As soon as said master gear moves in the opposite direction, the follower will engage in the next interdental space on the master gear and move it to its correct angular position. Thus, with this constructionjand for instance where the cam l i to bring the next tooth of the gear to be checked into operative engagement with feeler the lead of the master gear and, of course, effects the rotation ofthe gear to be checked therewith.

Instead of employing the lever IE to reciprocate thexmandrel, an alternate construction may be provided as shown in Figure 4. This comprises a bell crank 39 pivotally mounted at 40 upon ear M projecting from support 2. One arm It will be clear from the foregoing description that the gear tooth lead testing device shown in the drawings and described above has been illustrated and described in rather specific' detail. Obviously, many modifications,

changes, and departures from the above de- 'for'reciprocable movement thereon, said man drel serving to rotatably support a gear to be checked, a master gear secured tosaid mandrel, said master gear having, the teeth thereof tapered at one end, a tapered collar mounted on said mandrel coaxially with said master gear and abutting the axial end of said gear opposite to the end having the tapered teeth, a follower mounted on said base contacting the flanks of the teeth of the master gear, a rounded member mounted on said base in a plane parallel to the longitudinal axis of said mandrel and spaced from said follower member by a distance slightly greater than the axial length of said master gear said tapered collar being tapered suiiiciently to permit rotation of said 35 on in- 7 master gear when the said follower is in engagement therewith, said mandrel being axially movable with respect to said base whereby when said follower leaves engagement'with the teeth of said master gear said rounded member will engage the tapered ends of .said gear teeth in oiIset relationship to the extremity of the taper on the ends of said teeth whereby to cause sufvficient rotation of said master gear'to permit said follower to enter the next adjacent interdental space in said master gear on return axial movement of said mandrel and means on said base to check the lead of said gear to be checked.

2. Apparatus forhchecking the lead of the teeth of a gear, said apparatus comprising a base, a mandrel mounted for reciprocable movement longitudinally of said base, said mandrel serving to provide a rotatable support for a gear to be checked, a master gear secured to 7 said mandrel and coaxially arranged with re--'- spect to said gear to be checked, said..master gear having the teeth thereof tapered at one axial end, a tapered collar mounted on said mandrel coaxially with said master gear adjacent the axial end of said master gear supports v the end having the tapered teeth, a follower mounted on said base contacting the flanks of the teeth of' the master gear, a rounded member mounted on said'base in a plane parallel to 3? 9% 9? i r iiqil l a W9 H' $351 .rounded member will engage the tapered ends of said gear teeth in ofiset relationship to the extremity of the taper on the ends of said teeth whereby to v cause s'uflicient rotation of said -master gear to permit said follower to enter the next adjacent interdental space in said master ear on return axial movement of said mandrel.

and means on said base to engage the teeth of said gear to be checked in order to determine the accuracy of the lead thereof.

, 3 GEORGE C. RAZOR.

REFERENCES CITED The following references are of record the file of this patent:

UNITED STATES PATENTS Number Name Date 1,701,184 Hansen Feb. 5, 1929 1,854,244. Allison Apr. 19, 1932 2,057,970 Pelphrey Oct. 20, 1936 21 53? m g M y n 0 

